<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        var age=20;
        var name="guanyu";
      //  var xuexi=true;

        //typeof判断数据类型（判断基本数据类型使用）

        console.log(typeof age);//number
        console.log(typeof name );
        console.log(typeof xuexi);
        console.log(typeof user);
        console.log(typeof flag);
        console.log(typeof []);
    </script>
</body>
</html>